electric wire

Abstract

To provide an electric cable which is excellent in heat release characteristics of heat generated on a core wire of a conductor, to an outside.SOLUTION: An electric cable 1 comprises: a conductor core wire 10; an insulation coating 20 arranged so as to surround a periphery of the conductor core wire 10; and a coat layer 30 which is arranged so as to surround a periphery of the insulation coating 20, and is formed of materials including, a base material 31, and a mixture 32 which is excellent in heat transfer properties relative to the base material 31 and is mixed with the base material 31. An outer peripheral surface of the insulation coating 20 and an inner peripheral surface of the coat layer 30 have an irregularity fitting structure in which, one of them has a salient 20A protruding toward the other, in a radial direction of the electric cable 1, and the other of them has a recess 30A which is hollow to the one of them. The electric cable 1 has a soft heat transfer body 40 which is arranged so as to fill at least a part of a gap S between the salient 20A and the recess 30A.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electric wire including a conductor core, an insulating coating arranged to surround the outer periphery of the conductor core, and an outer jacket layer arranged to surround the outer periphery of the insulating coating. [Background technology]

[0002] BACKGROUND ART Electric wires having a structure in which a conductor core wire is covered with multiple layers such as an insulating coating and an outer layer (so-called sheath) have been proposed as electric wires for supplying power (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-176617 Summary of the Invention [Problem to be solved by the invention]

[0004] When an electric wire is actually used, the temperature of the conductor core generally rises due to Joule heat generated in the conductor core when current is applied. In the conventional electric wires described above, the conductor core is covered with multiple layers of insulating coatings, etc., making it difficult for the heat generated in the conductor core to be dissipated to the outside of the electric wire. Therefore, as the temperature of the conductor core rises, the temperature of the entire electric wire also rises, which may cause thermal deterioration of the insulating coating and outer layer. From the viewpoint of maintaining the quality and safety of the electric wire, it is desirable to suppress such deterioration.

[0005] An object of the present invention is to provide an electric wire that is excellent in the ability to dissipate heat generated in the conductor core to the outside. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the electric wire according to the present invention has the following features.

[0007] A conductor core wire, an insulating coating disposed so as to surround the outer periphery of the conductor core; an outer skin layer disposed so as to surround the outer periphery of the insulating coating, The skin layer is The material is composed of a base material and a mixture having a higher thermal conductivity than the base material and being mixed into the base material. It is an electric wire. [Effects of the Invention]

[0008] According to the present invention, the outer cover layer surrounding the insulating coating covering the conductor core wire is made of a material including a substrate and a mixture that has better heat conductivity than the substrate and is mixed into the substrate. Therefore, compared to when the outer cover layer is made of only the substrate, heat transfer from the insulating coating to the outer cover layer and heat dissipation from the outer cover layer to the outside of the electric wire can be more efficient. In other words, the overall heat dissipation performance of the multilayer structure including the insulating coating and the outer cover layer can be improved. Therefore, the electric wire having this configuration has excellent heat dissipation characteristics for heat generated in the conductor core wire to the outside.

[0009] Furthermore, as another effect, the electric wire having the above configuration has superior workability when routing the electric wire and freedom of routing route compared to when a heat-absorbing material (e.g., a metal case, etc.) is provided outside the outer skin layer.

[0010] In addition to the above configuration, the overall heat dissipation of the multilayer structure can be further improved by mixing a mixture with excellent thermal conductivity into the material constituting the insulating coating. However, mixing such a mixture into the material constituting the insulating coating may result in a decrease in the insulating properties of the insulating coating, or in deterioration of the insulating coating due to localized discharges occurring in minute gaps around the mixture that may occur when the mixture is exposed on the inner surface of the insulating coating. Therefore, if maintaining the functionality of the insulating coating is more important than further improving heat dissipation, it is preferable to compose the outer layer from a material containing a mixture with excellent thermal conductivity and the insulating coating from a material that does not contain such a mixture.

[0011] The present invention has been briefly described above. The details of the present invention will become clearer by reading the following detailed description of the invention (hereinafter referred to as "embodiments") with reference to the accompanying drawings. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view of an electric wire according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the electric wire according to the second embodiment. [Figure 3] FIG. 3 is an enlarged view of part A in FIG. [Figure 4] FIG. 4 is a cross-sectional view of the electric wire according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] First Embodiment Hereinafter, an electric wire 1 according to a first embodiment of the present invention will be described with reference to the drawings.

[0014] 1, the electric wire 1 includes a linear conductor core wire 10, a cylindrical insulating coating 20 arranged so as to surround the outer periphery of the conductor core wire 10, and a cylindrical outer jacket layer 30 arranged so as to surround the outer periphery of the insulating coating 20. The outer jacket layer 30 constitutes the outermost layer of the electric wire 1 and is also called a sheath.

[0015] The conductor core wire 10 may be a single conductor wire, a conductor bundle in which a plurality of conductor wires (element wires) are bundled, or a twisted wire in which a plurality of conductor wires are twisted. Here, the conductor wire is made of a conductive metal material, typically copper, copper alloy, aluminum, aluminum alloy, or the like.

[0016] In this example, the insulating coating 20 surrounds the outer periphery of the conductor core wire 10 so as to be in close contact with the entire outer periphery of the conductor core wire 10. The insulating coating 20 is made of an insulating resin material, typically cross-linked polyethylene. The insulating coating 20 is formed, for example, by extrusion molding the resin material that constitutes the insulating coating 20 so as to surround the conductor core wire 10.

[0017] In this example, the outer layer 30 (sheath) surrounds the outer periphery of the insulating coating 20 so as to be in close contact with the entire outer periphery of the insulating coating 20. The outer layer 30 is made of a material (i.e., a composite material) including an insulating base material 31 and a mixture 32 mixed into the base material 31. The effect of mixing the mixture 32 into the base material 31 will be described later.

[0018] The substrate 31 of the outer skin layer 30 is made of an insulating resin material, typically polyvinyl chloride or polyethylene. The mixture 32 is made of a material with better thermal conductivity than the substrate 31. For example, alumina particles or boron nitride filler can be used as the mixture 32. The thermal conductivity of the material (composite material) containing the substrate 31 and the mixture 32 is preferably greater than 0.29 W / m K.

[0019] The outer cover layer 30 can be formed, for example, by extruding the insulating coating 20 so as to surround the conductor core wire 10, and then extruding the material that constitutes the outer cover layer 30 so as to surround the insulating coating 20 that covers the conductor core wire 10. Alternatively, the outer cover layer 30 can be formed by extruding the resin material that constitutes the insulating coating 20 and the material that constitutes the outer cover layer 30 all at once so as to surround the conductor core wire 10.

[0020] The effect of mixing the mixture 32 into the base material 31 in the outer skin layer 30 will be described below. When the electric wire 1 is actually used, the temperature of the conductor core wire 10 rises due to Joule heat generated in the conductor core wire 10 when current is applied. In the electric wire 1, the conductor core wire 10 is covered in multiple layers with the insulating coating 20 and the outer skin layer 30, making it difficult for the heat generated in the conductor core wire 10 to dissipate to the outside of the electric wire 1. Therefore, as the temperature of the conductor core wire 10 rises, the temperature of the entire electric wire 1 also rises, which may cause thermal deterioration of the insulating coating 20 and the outer skin layer 30.

[0021] In this regard, in the electric wire 1 according to the first embodiment, the outer cover layer 30 surrounding the insulating cover 20 covering the conductor core wire 10 is made of a material including a substrate 31 and a mixture 32 that has better heat conductivity than the substrate 31 and is mixed into the substrate 31. Therefore, compared to when the outer cover layer 30 is made of only the substrate 31, heat transfer from the insulating cover 20 to the outer cover layer 30 and heat dissipation from the outer cover layer 30 to the outside of the electric wire 1 can be more efficient. In other words, the overall heat dissipation performance of the electric wire 1, which is a multilayer structure including the insulating cover 20 and the outer cover layer 30, can be improved. Furthermore, the electric wire 1 according to the first embodiment is superior in workability when routing the electric wire 1 and in flexibility of routing route compared to when a heat-absorbing material (for example, a metal case) is provided outside the outer cover layer 30.

[0022] Second Embodiment In the first embodiment described above, as shown in Fig. 1, the outer peripheral surface of the insulating coating 20 is configured as a smooth cylindrical outer peripheral surface, and the inner peripheral surface of the outer cover layer 30 is configured as a smooth cylindrical inner peripheral surface. In contrast, as in a second embodiment shown in Fig. 2, the outer peripheral surface of the insulating coating 20 may be provided with protrusions 20A at multiple positions in the circumferential direction, which protrude radially outward from the electric wire 1 and extend in the extending direction of the electric wire 1, and the inner peripheral surface of the outer cover layer 30 may be provided with recesses 30A at multiple positions in the circumferential direction, which recesses 30A are recessed radially outward from the electric wire 1 and extend in the extending direction of the electric wire 1, corresponding to the multiple protrusions 20A of the insulating coating 20. In this way, the outer peripheral surface of the insulating coating 20 and the inner peripheral surface of the outer cover layer 30 may have a recess-recess fitting structure in which the multiple protrusions 20A and the multiple recesses 30A are fitted together.

[0023] In the second embodiment shown in Fig. 2, the recess-projection fitting structure formed by the outer peripheral surface of the insulating coating 20 and the inner peripheral surface of the outer cover layer 30 allows the size of the area contributing to heat transfer between the insulating coating 20 and the outer cover layer 30 (i.e., the surface area of ​​the outer peripheral surface of the insulating coating 20 and the surface area of ​​the inner peripheral surface of the outer cover layer 30) to be larger than in the case where there is no recess-projection fitting structure (first embodiment shown in Fig. 1). This allows for more efficient heat transfer from the insulating coating 20 to the outer cover layer 30, thereby further improving the heat dissipation characteristics of the electric wire 1.

[0024] As in the first embodiment, the second embodiment shown in FIG. 2 may be manufactured by extruding the insulating coating 20 to surround the conductor core wire 10, and then extruding the material that constitutes the outer skin layer 30 to surround the insulating coating 20 that covers the conductor core wire 10, or by extruding the resin material that constitutes the insulating coating 20 and the material that constitutes the outer skin layer 30 all at once to surround the conductor core wire 10.

[0025] In the second embodiment shown in Fig. 2, when the outer skin layer 30 is formed, the material constituting the outer skin layer 30 penetrates between the multiple protrusions 20A formed on the outer peripheral surface of the insulating coating 20 and solidifies, thereby forming a concave-convex interlocking structure. However, if the outer peripheral surface of the insulating coating 20 and the inner peripheral surface of the outer skin layer 30 that form the concave-convex interlocking structure are not in perfect contact with each other, a minute gap S may be formed between the outer peripheral surface of the insulating coating 20 and the inner peripheral surface of the outer skin layer 30 (see Fig. 3). If air with poor thermal conductivity is present in this minute gap S, heat transfer from the insulating coating 20 to the outer skin layer 30 is hindered, which may result in a deterioration in the heat dissipation characteristics of the electric wire 1.

[0026] To address this issue, in the second embodiment shown in Fig. 2, a soft heat conductor 40, which has better heat conductivity than air, is disposed so as to fill part or all of the minute gap S (including the gap between the convex portion 20A and the concave portion 30A) between the outer peripheral surface of the insulating coating 20 and the inner peripheral surface of the outer skin layer 30, which constitute the concave-convex fitting structure (see Fig. 3). For example, grease is used as the soft heat conductor 40. This prevents the presence of air in the minute gap S (including the gap between the convex portion 20A and the concave portion 30A) from interfering with heat transfer from the insulating coating 20 to the outer skin layer 30.

[0027] When the soft heat conductor 40 is disposed, for example, the soft heat conductor 40 can be disposed in the minute gap S by simultaneously supplying the soft heat conductor 40 between the insulating coating 20 and the outer skin layer 30 when the insulating coating 20 and the outer skin layer 30 are extruded. Alternatively, the insulating coating 20 may be extruded to surround the conductor core wire 10, and then the soft heat conductor 40 may be applied to the outer peripheral surface of the insulating coating 20 by a method such as spraying, and then the material constituting the outer skin layer 30 may be extruded to surround the insulating coating 20 that covers the conductor core wire 10.

[0028] Third Embodiment 1 and 2, the outer cover layer 30 is disposed so as to surround (so as to be in close contact with) the outer periphery of a single insulating cover 20 that covers a single conductor core wire 10. In contrast, as in a third embodiment shown in FIG. 4, the outer cover layer 30 may be disposed so as to surround (so as to be in close contact with) the outer periphery of a plurality (two) of insulating covers 20 that individually cover a plurality (two in this example) of conductor core wires 10.

[0029] <Other forms> It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be adopted within the scope of the present invention. For example, the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. are possible as appropriate. In addition, the material, shape, dimensions, number, location, etc. of each component in the above-described embodiments are arbitrary and not limited as long as the present invention can be achieved.

[0030] For example, in the electric wire 1 according to the first embodiment, the insulating coating 20 does not contain a heat-conductive mixture like the mixture 32 in the outer cover layer 30. However, a heat-conductive mixture may also be mixed into the material constituting the insulating coating 20, as in the case of the outer cover layer 30. This allows for more efficient heat transfer from the conductor core wire 10 to the insulating coating 20, thereby further improving the overall heat dissipation of the electric wire 1, which has a multilayer structure. However, mixing a mixture into the material constituting the insulating coating 20 may result in a decrease in the insulating properties of the insulating coating 20 or in deterioration of the insulating coating 20 due to localized discharges occurring in minute gaps around the mixture that may occur when the mixture is exposed on the inner circumferential surface of the insulating coating 20. Therefore, when prioritizing the maintenance of the functionality of the insulating coating 20 over further improvement of heat dissipation, it is preferable to form the outer cover layer 30 from a resin material containing the mixture 32 with excellent heat conductivity and form the insulating coating 20 from a resin material that does not contain such a mixture, as in the electric wire 1 according to the first embodiment.

[0031] Furthermore, in the second embodiment described above, the outer peripheral surface of the insulating coating 20 and the inner peripheral surface of the outer skin layer 30 have a concave-convex fit structure, and the soft heat conductor 40 is disposed in the minute gap S between the outer peripheral surface of the insulating coating 20 and the inner peripheral surface of the outer skin layer 30. On the other hand, if the adhesion between the outer peripheral surface of the insulating coating 20 and the inner peripheral surface of the outer skin layer 30 is sufficient from the viewpoint of heat dissipation, the soft heat conductor 40 does not need to be disposed in the gap.

[0032] Furthermore, in the second embodiment, the convex portion 20A extending in the extension direction of the electric wire 1 and the concave portion 30A extending in the extension direction of the electric wire 1 are fitted together. However, a convex-concave fitting structure may be formed by fitting a convex portion and a concave portion having another shape together. For example, the concave-convex fitting structure may be formed by a convex portion and a concave portion extending in the circumferential direction of the electric wire 1, a convex portion and a concave portion extending spirally around the axis of the electric wire 1, a convex portion that is a mountain-shaped or columnar protrusion and a concave portion that receives the convex portion, or the like.

[0033] Furthermore, in the third embodiment, the outer circumferential surface of the insulating coating 20 that covers each of the multiple conductor core wires 10 is a smooth cylindrical outer circumferential surface. However, protrusions as shown in Fig. 2 may be provided on part or all of the outer circumferential surfaces of the insulating coating 20, and recesses for receiving the protrusions may be provided in the outer skin layer 30. In other words, the features of the second embodiment and the third embodiment may be combined.

[0034] Here, the features of the electric wire 1 according to the present invention described above will be briefly summarized and listed below in [1] to [3].

[0035] [1] A conductor core wire (10), an insulating coating (20) arranged to surround the outer periphery of the conductor core wire (10); an outer skin layer (30) arranged to surround the outer periphery of the insulating coating (20), The outer skin layer (30) is The heat exchanger is made of a material including a base material (31) and a mixture (32) that has better heat conductivity than the base material (31) and is mixed into the base material (31). Electric wire (1).

[0036] According to the electric wire having the configuration [1] above, the outer skin layer surrounding the insulating coating covering the conductor core wire is made of a material including a substrate and a mixture that has better heat conductivity than the substrate and is mixed into the substrate. Therefore, compared to when the outer skin layer is made of only the substrate, heat transfer from the insulating coating to the outer skin layer and heat dissipation from the outer skin layer to the outside of the electric wire can be performed more efficiently. In other words, the overall heat dissipation performance of the multilayer structure including the insulating coating and the outer skin layer can be improved. Therefore, the electric wire having this configuration has excellent heat dissipation characteristics for dissipating heat generated in the conductor core wire to the outside. Furthermore, as another effect, the electric wire having the above configuration has excellent workability when routing the electric wire and flexibility in routing the electric wire compared to when a heat-absorbing material (e.g., a metal case) is provided outside the outer skin layer.

[0037] [2] In the electric wire (1) described in [1] above, The outer peripheral surface of the insulating coating (20) and the inner peripheral surface of the outer skin layer (30) are The wire (1) has a projection (20A) projecting toward the other end in the radial direction thereof, and a recess (30A) recessed toward the other end in the radial direction thereof, and has a recess-projection fitting structure. Electric wire (1).

[0038] According to the electric wire having the configuration [2] above, the size of the area contributing to heat transfer between the insulating coating and the outer layer (i.e., the surface area of ​​the outer surface of the insulating coating and the surface area of ​​the inner surface of the outer layer) can be increased compared to when there is no concave-convex mating structure. This allows for more efficient heat transfer from the insulating coating to the outer layer, thereby further improving the heat dissipation characteristics of the electric wire. Note that such a concave-convex mating structure can be formed, for example, by collectively extruding the insulating coating and the outer layer so as to surround the conductor core wire.

[0039] [3] The electric wire (1) according to the above [2], The heating element further includes a soft heat transfer body (40) arranged to fill at least a part of the gap (S) between the convex portion (20A) and the concave portion (30A), Electric wire (1).

[0040] According to the electric wire having the configuration [3] above, a soft heat conductor is disposed so as to fill at least a portion of the gap between the convex portion and the concave portion that constitute the concave-convex fitting structure. This prevents air from being trapped between the convex portion and the concave portion, which would hinder heat transfer from the insulating coating to the outer skin layer. This allows for more efficient heat transfer from the insulating coating to the outer skin layer, thereby further improving the heat dissipation characteristics of the electric wire. Note that, for example, the heat conductor can be disposed in the gap by supplying a soft heat conductor between the insulating coating and the outer skin layer during the extrusion molding of the insulating coating and the outer skin layer. [Explanation of symbols]

[0041] 1 electric wire 10 Conductor core wire 20 Insulation coating 30 Outer skin layer 31 Base material 32 mixture 40 Heat Transfer Material S Gap

Claims

1. A conductor core wire, an insulating coating disposed so as to surround the outer periphery of the conductor core; an outer skin layer disposed so as to surround the outer periphery of the insulating coating, The skin layer is a material including a base material and a mixture having higher thermal conductivity than the base material and mixed into the base material, the material constituting the outermost layer of the electric wire; The outer peripheral surface of the insulating coating and the inner peripheral surface of the outer skin layer are The wire has a protrusion on one side that protrudes toward the other side in the radial direction of the wire, and a recess on the other side that is recessed toward the one side. Electric wire.

2. The electric wire according to claim 1, Further provided is a soft heat transfer material arranged to fill at least a part of the gap between the protrusion and the recess. Electric wire.

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